The awesome power of microbial genetics is based on the ability of geneticists to infer the components and properties of complex biological systems from the phenotypes of mutants. The systematic analysis of microbial phenotypes in thousands of bacterial genomes and metagenomes will be strengthened by a universal system to compare phenotypes across species and strains. The overall goal of this project is to build a such a system for ontology-based annotation of microbial phenotypes that will enable the efficient mining of relevant data to facilitate, and possibly one day automate, hypothesis generation leading to experimental studies. Under the first grant for this project, the Ontology of Microbial Phenotypes (OMP) was built and has so far been used to annotate 30% of the genes in Escherichia coli K-12. The work proposed in this application will develop and deploy a relational database for annotation data storage; continue development of the OMP; continue development of terms in the Evidence Ontology as needed for OMP annotation; develop a pipeline for generation of a synteny-based database of alleles and intraspecies ortholog groups (pangenes); continue improvement of the OMP web/database infrastructure; continue and expand annotation efforts in E. coli; begin annotation of Saccharomyces cerevisiae; and engage in community outreach. OMP is being developed in the context of multiple projects to improve phenotype annotation across all domains of life. As OMP encompasses some of the best-studied model genetic systems, it is in a position to influence the direction of the entire field o phenotype analysis. This project will stimulate the development of bioinformatics tools for phenotype analysis, which will be useful across all of genetics.